You can now set a sprite as a background in Background which will simplify a lot of games that just place sprites over a single image.

src/guecs/lel.cpp

@@ -11,27 +11,36 @@ namespace lel {
     grid_x(x),
     grid_y(y),
     grid_w(width),
-    grid_h(height),
-    cur(0, 0)
+    grid_h(height)
   {
   }
 
-  Parser::Parser() : cur(0, 0) { }
-
   void Parser::position(int x, int y, int width, int height) {
     grid_x = x;
     grid_y = y;
     grid_w = width;
     grid_h = height;
+
+    // used in GUIs for setting backgrounds
+    main = {
+      .x=grid_x,
+      .y=grid_y,
+      .w=grid_w,
+      .h=grid_h,
+      .mid_x=std::midpoint(grid_x, grid_x + grid_w),
+      .mid_y=std::midpoint(grid_y, grid_y + grid_h),
+      .max_w=grid_w,
+      .max_h=grid_h
+    };
   }
 
-  void Parser::id(std::string name) {
+  void Parser::id(const std::string& name) {
     if(name != "_") {
       assert(!cells.contains(name) && "duplicate cell name");
       cells.insert_or_assign(name, cur);
     }
 
-    cur = {cur.col + 1, cur.row};
+    cur = {.col=cur.col + 1, .row=cur.row};
     auto& row = grid.back();
     row.push_back(name);
   }
@@ -87,15 +96,18 @@ namespace lel {
   }
 
   void Parser::reset() {
-    cur = {0, 0};
+    cur = {.col=0, .row=0};
+    main = {.col=0, .row=0};
     grid.clear();
     cells.clear();
   }
 
   std::optional<std::string> Parser::hit(int x, int y) {
     for(auto& [name, cell] : cells) {
-      if((x >= cell.x && x <= cell.x + cell.w) &&
-          (y >= cell.y && y <= cell.y + cell.h)) {
+      if(name != "_MAIN" &&
+          (x >= cell.x && x <= cell.x + cell.w) &&
+          (y >= cell.y && y <= cell.y + cell.h))
+      {
         return name;
       }
     }
@@ -106,6 +118,7 @@ namespace lel {
   Cell center(int width, int height, Cell &parent) {
     Cell copy = parent;
 
+    // BUG: could I use std::midpoint here or am I even using this?
     copy.x = parent.mid_x - width / 2;
     copy.y = parent.mid_y - height / 2;
     copy.w = width;

src/guecs/lel_parser.cpp

@@ -86,7 +86,7 @@ static const int Parser_en_main = 1;
 
 #line 44 "src/guecs/lel_parser.rl"
 
-bool Parser::parse(std::string input) {
+bool Parser::parse(const std::string& input) {
   reset();
   int cs = 0;
   const char *start = nullptr;

src/guecs/lel_parser.rl

@@ -42,7 +42,7 @@ namespace lel {
 
 %% write data;
 
-bool Parser::parse(std::string input) {
+bool Parser::parse(const std::string& input) {
   reset();
   int cs = 0;
   const char *start = nullptr;

src/guecs/sfml/components.cpp

@@ -121,8 +121,36 @@ namespace guecs {
     assert(shape != nullptr && "failed to make rectangle");
   }
 
+  void Background::set_color(sf::Color c) {
+    color = c;
+  }
+
+  void Background::set_sprite(const std::string& name, bool stretch) {
+    auto sprite_texture = BACKEND->texture_get(name);
+
+    sprite = make_shared<sf::Sprite>(
+        *sprite_texture.texture,
+        sprite_texture.sprite->getTextureRect());
+
+    sprite->setPosition({float(x), float(y)});
+
+    if(stretch) {
+      auto bounds = sprite->getLocalBounds();
+
+      sprite->setScale({
+          float(w) / bounds.size.x,
+          float(h) / bounds.size.y});
+    }
+  }
+
   void Background::render(sf::RenderWindow& window) {
-    window.draw(*shape);
+    if(shape != nullptr) {
+      window.draw(*shape);
+    }
+
+    if(sprite != nullptr) {
+      window.draw(*sprite);
+    }
   }
 
   void Effect::init(lel::Cell &cell) {

src/guecs/ui.cpp

@@ -143,7 +143,7 @@ namespace guecs {
 
   bool UI::mouse(float x, float y, bool hover) {
     int action_count = 0;
-    // BUG: use lel::Parser.hit instead of this
+    // BUG: Is Parser::hit useful?
 
     query<lel::Cell>([&](auto ent, auto& cell) {
       if((x >= cell.x && x <= cell.x + cell.w) &&